issue getting unseen count from a mailbox

Hi,

I'm using wmbiff to monitor my imap mailboxes with a script that polls every minute:

eval "ssh $WMHOST \"doveadm mailbox status -u ldm 'messages unseen' $(printf %q "$WMBOX")\" 2>/dev/null" |
awk -F'[ =]' '{old=$3; new=$5} END {print old, new+0}' |
{ read old new; if [ $new -gt 0 ] ;then echo $new new; else echo $old; fi; }

If I haven't polled the mailbox before with mutt or another MUA then only the total message count will be returned, however if I peek at the mailbox with a MUA (without looking at any message) then the script returns the new message count.

How can I have dovecot (2.4.1 debian) always return the unseen message count in any case?

Thanks,